Ferritic stainless steel

Abstract

The invention provides ferritic stainless steels having excellent scale adhesion and thermal fatigue properties. The ferritic stainless steels include, by mass %, C: not more than 0.020%, Si: not more than 1.0%, Mn: not more than 1.0%, P: not more than 0.040%, S: not more than 0.030%, Cr: 16.0% to 20.0%, N: not more than 0.020%, Nb: 0.30% to 0.80%, Ti: from 4×(C %+N %) % to 0.50% wherein C % and N % indicate the C content and the N content (mass %), respectively, Al: less than 0.20%, Ni: 0.05% to 0.40%, and Co: 0.01% to 0.30%, the balance being Fe and inevitable impurities.

1 . A ferritic stainless steel comprising, by mass %, C: not more than 0.020%, Si: not more than 1.0%, Mn: not more than 1.0%, P: not more than 0.040%, S: not more than 0.030%, Cr: 16.0% to 20.0%, N: not more than 0.020%, Nb: 0.30% to 0.80%, Ti: from 4×(C %+N %) % to 0.50% wherein C % and N % indicate the C content and the N content (mass %), respectively, Al: less than 0.20%, Ni: 0.05% to 0.40%, and Co: 0.01% to 0.30%, the balance being Fe and inevitable impurities. 
     
     
         2 . The ferritic stainless steel according to  claim 1 , further comprising, by mass %, one or more selected from Ca: 0.0005% to 0.0030%, Mg: 0.0002% to 0.0020%, and B: 0.0002% to 0.0020%. 
     
     
         3 . The ferritic stainless steel according to  claim 1 , further comprising, by mass %, one or more selected from Mo: 0.02% to less than 0.10%, Cu: 0.01% to less than 0.20%, V: 0.01% to less than 0.50%, and W: 0.02% to less than 0.30%. 
     
     
         4 . The ferritic stainless steel according to  claim 2 , further comprising, by mass %, one or more selected from Mo: 0.02% to less than 0.10%, Cu: 0.01% to less than 0.20%, V: 0.01% to less than 0.50%, and W: 0.02% to less than 0.30%.